The
National Oceanic and Atmospheric Administration announced the 2005-2006
U.S. Winter Outlook today for the months December, January and February.
NOAA forecasters expect warmer-than-normal temperatures in most of
the U.S. The precipitation outlook is less certain, showing equal
chances of above, near or below normal precipitation for much of the
country.

“Even
though the average temperature over the three-month winter season
is forecast to be above normal in much of the country, there will
still be bouts of winter weather with cold temperatures and frozen
precipitation,” said retired Navy Vice Admiral Conrad
C. Lautenbacher, Jr., Ph.D., under secretary of commerce for oceans
and atmosphere and NOAA administrator.

NOAA does not expect La Niña and
El Niño/Southern Oscillation (ENSO) to play a role in this
winter’s forecast. Without ENSO forecasters look to other short-term
climate factors, like the North Atlantic Oscillation, in determining
the overall winter patterns. Under these conditions there tends to
be more variability in winter weather patterns across the nation,
especially in the Great Lakes region and the northeast U.S.

The
Outlook

The 2005-2006 U.S. Winter Outlook calls
for warmer-than-normal temperatures across much of the central and
western United States, including Alaska and Hawaii. The Midwest, the
Southern Californian coast and the East Coast have equal chances of
warmer, cooler, or near-normal temperatures this winter.

The precipitation outlook calls for wetter-than-normal
conditions across most of Arkansas, Louisiana, Oklahoma, and northeastern
Texas. Drier-than-normal conditions are expected across the Southwest
from Arizona to New Mexico.

As winter approaches, nearly 20 percent
of the nation is in some level of drought compared to around 30 percent
of the country this time last year as defined by the U.S. Drought
Monitor. For the sixth year in a row, drought remains a concern for
parts of the Northwest and northern Rockies. Wet or dry conditions
during the winter typically have a significant impact on drought conditions.
Winter-spring snow pack is particularly important in the West, as
much of the annual water supply comes from the springtime snow melt.
NOAA cautions it would take a number of significant winter snowstorms
to end the drought in the Pacific Northwest and northern Rockies.

What
Could Drive This Winter’s Weather?

Since early 2005 sea-surface temperatures
in the central-equatorial Pacific Ocean have been near normal. Near
normal sea-surface temperatures in the central-equatorial Pacific
Ocean are expected to continue for the next three to six months. Therefore,
it is unlikely that either the El Niño or La Niña phases
of the El Niño/Southern Oscillation (ENSO) cycle will be present
during the upcoming winter. As a result, one key climate feature that
could have a particularly large impact in U.S. winter weather, especially
along the East Coast, is the North Atlantic Oscillation or NAO.

The North Atlantic Oscillation often
changes its phase from week-to-week. During the positive phase the
jet stream shifts to the north of its usual position and the winter
weather features relatively warm days over much of the contiguous
U.S. In contrast, during the negative phase the jet stream shifts
to the south of its usual position. The negative phase of the NAO
features more Nor’easters and more frequent cold air outbreaks
and snowstorms, especially along the East Coast. Currently, the phase
of the NAO is difficult to anticipate more than one to two weeks in
advance.

Recognizing the demand to have more precision
with seasonal outlooks, NOAA’s Climate Prediction Center has
formed a Climate Test Bed. The Climate Test Bed is a collaborative
scientific effort among the operational, academic and research communities.
The mission of the Climate Test Bed is to accelerate the transfer
of atmospheric and oceanic research and development into operational
climate forecasts, products and applications. At present the Climate
Test Bed is focused on maximizing the use of NOAA’s Climate
Forecast System model in combination with other climate forecast tools
to improve U.S. seasonal precipitation and temperature outlooks.

The National Oceanic and Atmospheric
Administration, an agency of the U.S. Commerce Department, is dedicated
to enhancing economic security and national safety through the prediction
and research of weather and climate-related events and providing environmental
stewardship of our nation’s coastal and marine resources. Through
the emerging Global Earth Observation System of Systems (GEOSS), NOAA
is working with its federal partners and nearly 60 countries to develop
a global monitoring network that is as integrated as the planet it
observes.